A conventional bead ring winder of such a type rotates a rotation shaft, which supports a former, to wind a cord around the circumference of the former and form a bead ring having a predetermined winding diameter, which corresponds to the diameter of the former.
In such a structure, for example, as described in Patent Document 1, segments are arranged on a circular former to change the winding diameter of a bead ring to be formed. The segments are movable in the radial direction of the former. A bead ring having a diameter in accordance with the positions of the segments is formed.